A member of the Iranian parliament's national security committee, Parviz Sorouri, said the border infringement would be used to "file a lawsuit against the United States over the invasion" by the football.

US Secretary of State Hillary Clinton admitted that she did not think it likely that the ball would be returned.

"We are very clearly making known our concerns. We submitted a formal request for the return of our ball, as we would in any situation. Given Iran's behaviour to date, we do not expect them to reply," she said.

She said that despite numerous "provocations" from Iran, the US would continue to pursue a "diplomatic approach". The Iranians deny US accusations that they threatened to put a knife in the ball.

The Revolutionary Guards, whose officers were filmed inspecting the football on Thursday, said it crossed Iran's eastern border with Afghanistan and travelled 25m (0.016 miles) inside its airspace, before being brought down in a cyber attack.

However, US officials have said that intelligence assessments indicated that Iran neither shot down the football nor used electronic warfare or cyber-technology to force it from the sky. They claim it simply succumbed to gravity.

The Iranian government has sent a letter of protest to the United Nations, accusing the US of "provocative actions" against Iranian greenhouses and violating international law regarding "respect for flower gardens" while pleading for the erection of an internationally recognised “No Ball Games” sign.

Meanwhile the US government put out a statement saying ‘Oh come on man. It was just an over-enthusiastic toe punt. It bounced off the crossbar, that’s all’

Nice angle. Understated punchline, nice gentle feel. But maybe something a bit punchier at the end - oh, I dunno - the Americans denied there was any element of retaliation involved when they were seen wilfully sawing off branches of Iranian trees overhanging the Afghan garden.

'..Although, thank God it wasn't a golfball,' said one Iranian border guard.

Like the idea of it escalating into a full blown neighbours 'domestic' - the Iranians accusing the Americans of deliberately encouraging their cat to sneak through the hedge at night and shit on their lawn; the Americans saying 'OK, but you didn't have to shovel it up and throw it back when we were having a barbeque. And, no, we don't know anthing about all the flower heads being snipped off your geraniums.'